摘要
为分析近60 a来中国华西地区秋季降水的时空变化特征及成因,采用1961-2020年CN05.1逐日降水量资料、NCEP/NCAR再分析资料以及采用线性趋势、小波分析以及合成分析等统计方法对华西地区秋季降水时空分布及环流背景进行分析。结果表明:中国华西地区近60 a来秋季累积降水、9月、10月和11月降水气候平均值分别为235.8 mm、127.9 mm、75.9 mm和32 mm,且存在明显“偏多—偏少—偏多”的年代际变化特征。受地形和环流影响,华西地区秋季降水空间分布极不均匀,其中季节累积降水在华西地区东部和西南部偏多,而西部和北部地区偏少,且存在多个降水大值中心,而9-11月各月降水大值中心逐渐向东南部移动,量级也随之减小。华西地区秋季降水指数能够较好地表征秋季降水的基本变化特征,基于该指数的小波分析结果表明华西地区秋季降水存在3 a、6 a、9 a和17 a的周期变化。华西地区秋季降水偏多和偏少年大气环流呈反位相变化特征,即降水偏多年巴尔喀什湖大槽加深,西太平洋副热带高压偏强且西伸北抬,源于西太平洋地区的水汽在华西地区辐合上升,有利于降水增加,反之亦然。
In order to explore the temporal and spatial variation characteristics and causes of autumn precipitation in West China in recent 60 years,combined with CN05.1 daily precipitation data and NCEP/NCAR reanalysis data from 1961to 2020,the temporal and spatial distribution and circulation background of autumn precipitation in West China are analyzed and studied by using statistical analysis methods such as linear trend,wavelet analysis and composite analysis.The results show that the climatic average values of autumn cumulative precipitation,September,October and November precipitation in West China in recent 60 years are 235.8 mm,127.9 mm,75.9 mm and 32 mm respectively,and there is an obvious interdecadal variation characteristic of"more-less-more".Affected by topography and circulation,the spatial distribution of autumn precipitation in West China is extremely uneven.The seasonal cumulative precipitation in autumn is mainly characterized by more precipitation in the East and southwest of West China,while less precipitation in the West and North,and there are several large precipitation value centers.From September to November,the large precipitation value centers gradually move to the southeast,and the magnitude decreases.The autumn precipitation index in West China can better reflect the basic variation characteristics of autumn precipitation,and the result of Morlet wavelet analysis based on this index shows that the autumn precipitation in West China has periodic changes of 3 years,6 years,9 years and 17 years.In the autumn drought and flood years in West China,the atmospheric circulation shows the characteristics of inverse phase change.In the flood years,the trough of Lake Balkash deepens abnormally,the West Pacific subtropical high locates more westward and northward with stronger intensity,and the water vapor from the West Pacific region converges and rises in West China,which is conducive to the increase of precipitation,and vice versa.
作者
邓欢
华维
冯亮亮
夏昌基
邓浩
DENG Huan;HUA Wei;FENG Liangliang;XIA Changji;DENG Hao(College of Atmospheric Sciences/Plateau Atmosphere and Environment Key Laboratory of Sichuan Province/Engineering Laboratory of Meteorological Disasters Prediction and Early Warning of Sichuan Province,Chengdu University of Information Technology,Chengdu 610225,China;Nansen-Zhu International Research Centre,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China)
出处
《成都信息工程大学学报》
2022年第5期584-591,共8页
Journal of Chengdu University of Information Technology
基金
国家自然科学基金项目(41775072,42075019)
国家重点研发计划项目(2018YFC1505702)
第二次青藏高原综合科学考察研究项目(2019QZKK010203)
四川省杰出青年科技人才计划项目(2019JDJQ0001)
关键词
气象学
气候变化
华西地区
秋季降水
时空特征
合成分析
meteorology
climate change
West China
autumn precipitation
temporal and spatial variation
composite analysis
